WORKSHOP PAPER
Charge-domain signal clamping and extended dark signal cancellation for automotive CMOS image sensors
Shinyeol Choi1, Haneol Seo1, Kyung-min Kim1, Minwoo Lee1, Mira Lee1, Jihun Shin1, Jinkyeong Heo1, Youngtae Jang1, Min-Sun Keel1, Juhyun Ko1, Jesuk Lee1
1System LSI Division, Samsung Electronics Co., Ltd., Hwaseong, Gyeonggi-do, Korea

Abstract

This paper presents circuit techniques to enhance the image quality of CMOS image sensors for automotive applications under harsh conditions such as high illumination and high temperature. A charge-domain clamping at the unit pixel level is proposed to constrain the voltage swing within the ADC full-scale range, and improve linearity of pixel source follower. To maintain black level stability at high temperatures, an extended dark signal cancellation scheme is introduced, to increase temperature coverage without sacrificing A/D conversion time. From the measurement results, the proposed charge-domain clamping improves the linearity of pixel output by 27.8% compared to conventional methods, and the extended dark signal cancellation ensures stable black level at a temperature up to Tj 120°C at 11-ms exposure time in a given A/D conversion time.
Year: 2025
Workshop: IISW
URL: https://doi.org/10.60928/1l4s-st0k
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Keywords

CMOS image sensors, automotive applications, charge-domain clamping, extended dark signal cancellation, image quality,

References

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